American Sarai Sierra went missing last Monday, the final day of her 'trip of a lifetime' to Turkey. / Derek Fahsbender via AP

by Victor Kotsev, Special for USA TODAY

by Victor Kotsev, Special for USA TODAY

ISTANBUL - The New York City woman who vanished in Turkey was spotted on security cameras walking alone two days before she was due to depart for home, police said Tuesday.

The camera footage shows Sarai Sierra eating alone in the food court of a shopping mall near the room she had rented in a downscale part of Istanbul, police told the Turkish newspaper Zaman. She was dressed in jeans, a brown leather jacket and a winter hat, with her hands in her pockets.

Another image shows her walking along a main shopping street, wearing earphones.

That was on Jan. 20, two days before Sierra, 33, was due to fly back to Newark and rejoin her husband and two young children at their Staten Island home. She had traveled to Turkey for what friends described as a "dream trip" to photograph the city.

Her husband, Steven Diaz-Sierra, and brother David Jimenez say Sierra was in contact with the family the day after the security footage was taken. They say it was her first trip out of the United States, but that she expressed no uneasiness about her situation.

Both men arrived in Istanbul late Monday to help police in their investigation. The Turkish newspaper Hurriyet quoted unnamed police sources as saying investigators were not notified about the disappearance until Jan. 25.

Police are focusing on Sierra's travels and whom she was in contact with during her trip. She had planned out much of her trip over the Internet, discussing it with contacts on social media sites such as Instagram.

Sierra took a side trip to Amsterdam from Istanbul on Jan. 15. She stayed only one day before arriving in Munich on Jan. 16. She remained there for three days and returned to Istanbul on Jan. 19.

Diaz-Sierra told the Staten Island Advance that his wife had been in contact over the Internet with a Dutch tour guide she had met in Istanbul. She rented a room from Yigit Yetmez, a student at the local Bilgi University who said he rented his spare room out to Sierra after they connected on the Internet, according to Turkish news media.

Although the Beyoglu neighborhood in which Sierra was staying is an upscale area full of nightlife and historic landmarks, Komurcu Zeynel Street, where her room is located, is one of the more dangerous parts of the district. The district is home to immigrant communities made up of Roma and Africans, and it is known for heroin dealing and prostitution.

"No pictures, no pictures, goodbye," men from a nearby café shouted at journalists walking by to photograph the apartment where Sierra stayed on 20 Kömürcü Zeynel St.